KR100521576B1 - Liquid-crystal display device and method of signal transmission thereof - Google Patents

Abstract

The number of transmission lines required in the LCD device is reduced. The first interface circuit provided in the controller circuit receives the polarity inversion signal and the horizontal scanning signal in different active mode periods in parallel. The first interface circuit generates a serial signal from the polarity inversion signal and the horizontal scan signal, and transmits the serial signal to the data electrode driving circuit through the transmission line (s). The second interface circuit provided in the data electrode driving circuit regenerates the polarity inversion signal and the horizontal scanning signal in parallel from the serial signal.

Description

Liquid crystal display device and signal transmission method {LIQUID-CRYSTAL DISPLAY DEVICE AND METHOD OF SIGNAL TRANSMISSION THEREOF}

Background of the Invention

Field of invention

The present invention relates to a liquid crystal display (LCD) device, and more particularly to an LCD device having a relatively long transmission line for transmitting an internal signal, and a signal transmission method in the device.

Description of the related technology

In the LCD device, in general, the controller circuit outputs an image input signal, a polarity inversion signal, a horizontal scan signal, and a vertical scan signal to be displayed. The image input signal is provided to the data electrode driving circuit in synchronization with the horizontal scan signal. The pixel data signal corresponding to the image input signal thus provided is polarized inverted according to the polarity inversion signal and transmitted from the data electrode driving circuit to each data electrode of the LCD panel. The vertical scan signal is provided to the scan electrode driving circuit. The scan signal is transmitted to the scan electrode driving circuit in synchronism with the vertical scan signal by the data driving circuit. The pixel data signal is provided to a predetermined pixel area on the panel selected by the scanning signal, and displays an image on the screen of the panel according to the pixel data signal. The data electrode driver circuit includes data electrode driver (s). The scan electrode driver circuit includes scan electrode driver (s).

1 shows a circuit configuration of an example of a prior art LCD of the type described above. The apparatus includes an LCD panel 1, a controller circuit 2, a gray scale power supply circuit 3, a data electrode driving circuit 4, and a scan electrode driving circuit 5.

The LCD panel 1 includes a color filter that generates a color image by dividing each pixel into sub-pixels of red (R), green (G), and blue (B). The panel 1 has n data electrodes X1 to Xn (where n is a positive integer greater than 2) to which the corresponding sub-pixel data signal D is applied, and m to which the corresponding scanning signal V is applied. Scan electrodes Y1 to Ym (where m is a positive integer greater than 2), and sub-pixel regions (not shown) formed at each intersection of the data electrodes X1 to Xn and the scan electrodes Y1 to Ym. It includes more. A corresponding sub-pixel data signal D is applied to a predetermined sub-pixel area selected by the scanning signal V, and a color on a screen (not shown) of the panel 1 is in accordance with the signal D. Display the image.

For example, the controller circuit 2 formed by an application specific integrated circuit (ASIC) is configured to generate 8-bit red data DR, 8-bit green data DG, and 8-bit blue data DB. It is provided to the electrode drive circuit 4. These data DR, DG, and DB are provided to the circuit 2 from the outside of the LCD device. The circuit 2 includes a horizontal scan signal PH, a vertical scan signal PV, and a polarity inversion signal POL based on a horizontal sync signal SH and a vertical sync signal SV provided from an outside of the LCD device. Create The polarity inversion signal POL is used for alternatingly driving the panel 1. The circuit 2 simultaneously supplies the horizontal scan signal PH and the polarity inversion signal POL thus generated to the data electrode driving circuit 4 in the voltage mode, and provides the generated scan signal PV in the voltage mode. The scan electrode driving circuit 5 is provided. The circuit 2 also supplies the red scale voltage data DGR, the green scale voltage data DGG, and the blue scale voltage data DGB to the gray scale power supply circuit 3. The data DGR, DGG, and DGB are used to provide a predetermined gradation to the data DR, DG, and DB, respectively, through gamma (γ) correction.

The gray scale power supply circuit 3 includes three digital-to-analog converter (DAC) circuits 11 ₁ , 11 ₂ , and 11 ₃ and 54 voltage follower circuits 12 ₁ to 12 ₅₄ as shown in FIG. 2. It includes. The DAC circuit 11 ₁ converts the digital red scale voltage data DGR into 18 analog red scale voltages V _R0 to V _R17 , and the circuit 11 ₁ then converts the voltages V _R0 to V to _R17 ) to the voltage follower circuits 12 ₁ to 12 ₁₈ , respectively. Similarly, the DAC circuit 1 1 ₂ converts the digital green scale voltage data DGG to 18 analog green scale voltages V _G0 to V _G17 , and then the circuit 1 1 ₂ performs the voltage V _G0 to _VG17 ) are provided to the voltage follower circuits 12 ₁₉ to 12 ₃₆ , respectively. The DAC circuit 11 ₃ converts the digital blue scale voltage data (DGB) into 18 analog blue scale voltages (V _B0 to V _B17 ), and then the circuit 11 _{3 is} connected to the voltages (V _B0 to V). _B17 ) to the voltage follower circuits 12 ₃₇ to 12 ₅₄ , respectively. The analog red scale voltages V _R0 to V _R17 , the analog green scale voltages V _G0 to V _G17 , and the analog blue scale voltages V _B0 to V _B17 each represent red data DR, green data DG, And γ-correction for each of the blue data (DB). The voltage follower circuits 12 ₁ through 12 _{54 receive} analog red, green, and blue scale voltages V _R0 through V _R17 , V _G0 through V _G17 , or V _B0 through V _B17 , respectively, at high input impedance, These are output to the data electrode drive circuit 4 at low output impedance.

The data electrode driver circuit 4 includes k data electrode drivers 4 ₁ to 4 _k (k is a natural number). Each of the data electrode drivers 4 ₁ to 4 _k is red, green, and based on red, green, and blue scale voltages V _R0 to V _R17 , V _G0 to V _G17 , and / or V _B0 to V _B17 . A predetermined gamma-correction is applied to the blue data DR, DG, and / or DB to provide a gradation. The circuit 4 then converts the red, green and blue data (DR, DG, and / or DB) thus corrected into 384 sub-pixel data signals D and converts the signal D into a panel. The data is output to the data electrodes X1 to Xn on (1).

For example, when the panel 1 is designed for Super eXtended Graphic Array (SXGA) resolution or mode, the panel 1 has 1280 pixels (horizontal) x 1024 pixels (vertical) as a whole. In this case, the number of sub-pixels is 3840 pixels (horizontal) x 1024 pixels (vertical), because each pixel has three sub-pixels: red sub-pixel, green sub-pixel, and blue sub-pixel. Because it is formed. Here, (3840 pixels) / (384 data signals) = 10 (pixels / data signals). Thus, the total number of data electrode driver circuits is 10; That is, k = 10. This means that the data electrode driver circuit 4 includes ten data electrode drivers 4 ₁ to 4 ₁₀ . The following description is carried out under the conditions detailed above.

The data electrode drivers 4 ₁ to 4 ₁₀ have the same circuit configuration except for the subscripts of each element and each signal. Therefore, only one data electrode driver 4 ₁ will be described below.

The data electrode driver 4 ₁ of the data electrode driver circuit 4 includes three multiplexer (MPX) circuits 13 ₁ to 13 ₃ , three 8-bit DACs (digital-analog), as shown in FIG. 3. Converter) circuits 14 ₁ to 14 ₃ , and 384 voltage follower circuits 15 ₁ to 15 ₃₈₄ .

The MPX circuit 13 ₁ receives the red scale voltages V _R0 to V _R17 from the gray scale power supply circuit 3 and according to the polarity inversion signal POL from the controller circuit 2, the red scale voltage V _R0. To V _R8 ) or sets of red scale voltages V _R9 to V _R17 are alternately provided to the DAC circuit 14 ₁ . Similarly, MPX circuit (13 ₂₎ is a gray-scale power supply circuit (3) Green scale voltages (V _G0 to V _G17) receives, green scale voltages (V _G0 to V _G8) in accordance with the polarity inversion signal (POL) to from The set of or green scale voltages V _G9 to V _G17 are alternately provided to the DAC circuit 14 ₂ . The MPX circuit 13 ₃ receives the blue scale voltages V _B0 to V _B17 from the blue scale power supply circuit 3 and sets a set of blue scale voltages V _B0 to V _B8 according to the polarity inversion signal POL. The set of blue scale voltages V _B9 to V _B17 is alternately provided to the DAC circuit 14 ₂ .

The DAC circuit 14 ₁ is connected from the controller circuit 2 based on the set of red scale voltages V _R0 to V _R8 or the set of red scale voltages V _R9 to V _R17 from the MPX circuit 13 ₁ . A predetermined gamma-correction is applied to the 8-bit red data DR to provide gradation to the red data DR. In addition, the DAC circuit 14 ₁ converts the digital red data DR thus corrected into an analog red data signal so as to correspond to the corresponding voltage follower circuits 15 ₁ , 15 ₄ , 15 ₇ ,..., And 15 _382. To provide. Similarly, the DAC circuit 14 ₂ is based on the set of green scale voltages V _G0 to V _G8 or the set of green scale voltages V _G9 to V _G17 from the MPX circuit 13 ₂ . A predetermined gamma-correction is applied to the 8-bit green data DG from) to provide a gradation to the green data DG. In addition, the DAC circuit 14 ₂ converts the digital green data DG thus corrected into an analog green data signal so that the corresponding voltage follower circuits 15 ₂ , 15 ₅ , 15 ₈ ,..., And 15 ₃₈₃ To provide. The DAC circuit 14 ₃ is connected from the controller circuit 2 based on the set of blue scale voltages V _B0 to V _B8 or the set of blue scale voltages V _B9 to V _B17 from the MPX circuit 13 ₃ . A predetermined gamma-correction is applied to the 8-bit blue data DG to provide gradation to the blue data DB. In addition, the DAC circuit 14 ₃ converts the digital blue data DB thus corrected into an analog blue data signal so that the corresponding voltage follower circuits 15 ₃ , 15 ₆ , 15 ₉ ,..., And 15 ₃₈₄ To provide.

Voltage follower circuits 15 ₁ through 15 ₃₈₄ receive corresponding red, green, and blue data signals at high input impedance, and sub-pixel data signals (i) at corresponding data electrodes X1 through Xn at low output impedance. D) transmit as.

The scan electrode driving circuit 5 generates the scan signal V in synchronization with the vertical scan signal PV transmitted from the controller circuit 2. The circuit 5 then provides the generated scan signal V to the corresponding scan electrodes Y1 to Ym.

The controller circuit 2 and the gray scale power supply circuit 3 are mounted on a printed wiring board (PWB) 16 as shown in FIG. The ten data electrode drive circuits 4 ₁ to 4 ₁₀ are mounted on ten carrier tapes, each electrically connecting the PWB 16 to the panel 1, so that ten tape carrier packages (TCP) ( 17 ₁ to 17 ₁₀ ). The PWB 16 is attached to the top of the backlight unit 18 as shown in FIG. The backlight unit 18 having an almost wedge shaped cross section is located on the back side of the panel 1. The backlight unit 18 may include a point light source (for example, a white lamp) or a linear light source (for example, a fluorescent lamp), and an optical diffuser for diffusing light from the light source to form a planar light source. Include. Since the panel 1 does not emit light by itself, the unit 18 is used to uniformly illuminate the back side of the panel 1.

In the prior art LCD device of FIG. 1, as shown in FIG. 6, the polarity inversion signal POL and the horizontal scanning signal PH output in parallel from the controller circuit 2 are at their different timings in their active mode periods. Has Specifically, when the horizontal scan signal PH is in the active mode (ie, the logic high level), the polarity inversion signal POL is not in the active mode but in the ineffective state. On the other hand, when the polarity inversion signal POL is in the active mode, the horizontal scanning signal PH is not in the active mode.

The red scale voltages V _R0 to V _R17 provided from the gray scale power supply circuit 3 are input to the MPX circuit 13 _{1 in} synchronization with the horizontal scan signal PH. Thereafter, a set of red scale voltages V _R0 to V _R8 or a set of red scale voltages V _R9 to V _R17 are alternately provided to the DAC circuit 14 ₁ in accordance with the polarity inversion signal POL. Similarly, the green scale voltages V _G0 to V _G17 provided from the gray scale power supply circuit 3 are input to the MPX circuit 13 _{2 in} synchronization with the horizontal scan signal PH. Then, in accordance with the polarity inversion signal POL, a set of green scale voltages V _G0 to V _G8 or a set of green scale voltages V _G9 to V _G17 are alternately provided to the DAC circuit 14 ₂ . The blue scale voltages V _B0 to V _B17 provided from the gray scale power supply circuit ₃ are input to the MPX circuit 13 _{3 in} synchronization with the horizontal scan signal PH. Thereafter, a set of blue scale voltages V _B0 to V _B8 or a set of blue scale voltages V _B9 to V _B17 are alternately provided to the DAC circuit 14 ₃ in accordance with the polarity inversion signal POL.

8-bit red provided from the controller circuit 2 and input to the DAC circuit 14 ₁ based on the set of red scale voltages V _R0 to V _R8 or the set of red scale voltages V _R9 to V _R17 . Gamma-correction is performed in the DAC circuit 14 ₁ with respect to the data DR to provide a gradient to the data DR. At the same time, the red data DR is converted into an analog red data signal. The analog red data signal thus obtained is provided to corresponding voltage follower circuits 15 ₁ , 15 ₄ , 15 ₇ ,..., And 15 ₃₈₂ . Similarly, based on the set of green scale voltages V _G0 to V _G8 or the set of green scale voltages V _G9 to V _G17 , 8 provided from the controller circuit ₂ and input to the DAC circuit 14 ₂ . Gamma-correction is performed in the DAC circuit 14 ₂ for the bit green data DG to provide a gradation for the data DG. At the same time, the green data DG is converted into an analog green data signal. The analog green data signal thus obtained is provided to corresponding voltage follower circuits 15 ₂ , 15 ₅ , 15 ₈ ,..., And 15 ₃₈₃ . 8-bit blue provided from controller circuit 2 and input to DAC circuit 14 ₃ , based on a set of blue scale voltages V _B0 to V _B8 or a set of blue scale voltages V _B9 to V _B17 . Gamma-correction is performed in the DAC circuit 14 ₃ with respect to the data DB, providing a gradation to the data DB. At the same time, the blue data DB is converted into an analog blue data signal. The analog blue data signal thus obtained is provided to corresponding voltage follower circuits 15 ₃ , 15 ₆ , 15 ₈ ,..., And 15 ₃₈₄ .

The analog red, green, and blue data signals thus obtained are transmitted as corresponding sub-data signals D to the corresponding data electrodes X1 to Xn.

The vertical scan signal PV is provided from the controller circuit 2 to the scan electrode drive circuit 5. The scan signal V is generated by the circuit 5 and output to the scan electrodes Y1 to Ym in synchronization with the signal PV. In the panel 1, the sub-pixel data signal D is provided to a predetermined sub-pixel area selected by the scanning signal V, and the panel 1 is in accordance with the sub-pixel data signal D thus provided. Will display a color image on the screen (not shown).

In the above-described conventional LCD device, there are the following problems.

Horizontal and vertical scan signals (PH and PV), polarity inversion signals (POL), red, green, and blue data (DR, DG, and DB), red scale voltages (V _R0 to V _R17 ), green scale voltages (V) _G0 to V _G17 , and the blue scale voltages V _B0 to V _B17 are all transmitted in voltage mode. Therefore, if the LCD device of the prior art is designed relatively large, the transmission line for these signals or data will be relatively long. In this case, the signals and / or data transmitted in this manner are influenced by the distributed constants or parameters of the transmission line (for example, distribution capacitance, inductance, and resistance). Phase rotation occurs. As a result, a problem of deterioration of image quality may occur.

In addition, high frequency noise is generated because distributed capacitors of the transmission line are charged and discharged in response to the voltage change of each signal. These noises cause electromagnetic interference in other electronic devices. This is another issue.

In addition, each of the horizontal and vertical scan signals PH and PV requires one transmission line. The polarity inversion signal POL requires one transmission line. 8-bit red data DR requires eight transmission lines. Eight-bit green data (DG) requires eight transmission lines. 8-bit blue data (DB) requires 8 transmission lines. The red scale voltages V _R0 to V _R17 require 18 transmission lines. The green scale voltages V _G0 to V _G17 require 18 transmission lines. The blue scale voltages V _B0 to V _B17 require 18 transmission lines. Therefore, if the size of the PWB 16 and / or TCP 17 ₁ to 17 ₁₀ is designed to be small, there will be a problem that it is difficult or impossible to form the necessary transmission lines as needed. Therefore, when downsizing the LCD device, it is necessary to reduce the number of necessary transmission lines as much as possible.

It is therefore an object of the present invention to provide an LCD device which reduces the number of required transmission lines and to provide a method for transmitting signals within the device.

Another object of the present invention is to provide an LCD device which prevents or suppresses phase rotation and noise in a high frequency region of a signal transmitted in a device, and provides a method for transmitting a signal in the device.

Another object of the present invention is to provide an LCD device which prevents EMI to another electronic device, and to provide a method for transmitting a signal in the device.

The above-mentioned objects and other objects not mentioned will be easily understood by those skilled in the art through the following description.

According to a first aspect of the invention, an LCD device is provided, wherein the LCD device comprises:

A liquid crystal display (LCD) panel having a data electrode for receiving a pixel data signal, a scan electrode for receiving a scan signal, and a pixel region located at an intersection of the data electrode and the scan electrode;

Receive an image input signal in synchronization with a horizontal scan signal, polarize the pixel data signal corresponding to the image input signal based on the polarity inversion signal, and apply the polarity inverted pixel data signal to the data electrode of the panel. A data electrode driving circuit for transmitting the data;

A scan electrode driving circuit for transmitting a scan signal to the scan electrode of the panel in synchronization with a vertical scan signal; And

A controller circuit for outputting said image input signal, said polarity inversion signal, said horizontal scanning signal and said vertical scanning signal,

A portion of the pixel region is selected by the scan signal,

The pixel data signal is provided in the portion of the pixel region, and displays an image corresponding to the applied pixel data signal,

The controller circuit receives the polarity inversion signal and the horizontal scanning signal in parallel with different active mode periods, generates a serial signal from the polarity inversion signal and the horizontal scanning signal, and transmits the serial signal to the transmission line (s). A first interface circuit for transmitting to said data electrode driving circuit via;

The data electrode driving circuit includes a second interface circuit which regenerates the polarity inversion signal and the horizontal scanning signal in parallel from the serial signal.

In the LCD device according to the first aspect of the present invention, the first interface circuit is provided in the controller circuit. The first interface circuit receives the polarity inversion signal and the horizontal scanning signal in parallel with different active mode periods. The first interface circuit also generates a serial signal from the polarity inversion signal and the horizontal scan signal, and transmits the serial signal to the data electrode driving circuit via the transmission line (s).

In addition, the second interface circuit is provided in the data electrode driving circuit. The second interface circuit regenerates the polarity inversion signal and the horizontal scanning signal in parallel from the serial signal.

Therefore, the total number of required transmission lines can be reduced, thereby making it possible to cope with the miniaturization of the LCD device.

In a preferred embodiment of the device according to the first aspect of the invention, the device has a configuration in which the serial signal is transmitted in the current mode. In this embodiment, the serial signal is transmitted in the current mode, and therefore, phase rotation in the high frequency region of the signal transmitted in the apparatus can be prevented. This means that image quality can be improved and at the same time high frequency noise can be reduced and EMI to other electronic devices can be prevented.

In another preferred embodiment of the apparatus according to the first aspect of the invention, the first interface circuit converts the polarity inversion signal and the horizontal scanning signal transmitted in parallel into a first series signal voltage in parallel. Series converter circuits; And a voltage-current converter circuit for converting the first series signal voltage into a signal current. The signal current is output to the transmission line (s). The second interface circuit includes a current-voltage converter circuit for converting the signal current into a second signal voltage; And a series-parallel converter circuit for converting the second signal voltage into the polarity inversion signal and the horizontal scan signal in parallel.

In another preferred embodiment of the apparatus according to the first aspect of the present invention, the data electrode driving circuit includes at least one data electrode driving portion according to the number of the data electrodes.

According to a second aspect of the present invention, a method for transmitting a signal in an LCD device is provided. The device is:

A liquid crystal display (LCD) panel having a data electrode for receiving a pixel data signal, a scan electrode for receiving a scan signal, and a pixel region located at an intersection of the data electrode and the scan electrode;

Receive an image input signal in synchronization with a horizontal scan signal, polarize the pixel data signal corresponding to the image input signal based on the polarity inversion signal, and apply the polarity inverted pixel data signal to the data electrode of the panel. A data electrode driving circuit for transmitting the data;

A scan electrode driving circuit for transmitting a scan signal to the scan electrode of the panel in synchronization with a vertical scan signal; And

A controller circuit for outputting said image input signal, said polarity inversion signal, said horizontal scanning signal and said vertical scanning signal,

A portion of the pixel region is selected by the scan signal,

The pixel data signal is provided to the portion of the pixel region and displays an image corresponding to the applied pixel data signal.

The controller circuit receives the polarity inversion signal and the horizontal scanning signal in parallel with different active mode periods, generates a serial signal from the polarity inversion signal and the horizontal scanning signal, and transmits the serial signal to the transmission line (s). Transfer to the data electrode driving circuit through.

The data electrode driving circuit regenerates the polarity inversion signal and the horizontal scanning signal in parallel from the series signal.

In the method for transmitting signals in the LCD device according to the second aspect of the present invention, the controller circuit and the data electrode driving circuit operate in the same manner as the controller circuit and the data electrode driving circuit of the LCD device according to the first aspect of the present invention. Do this. Thus, the same effect as in the apparatus of the first embodiment can be achieved.

In a preferred embodiment of the method according to the second aspect of the invention, the serial signal is transmitted in current mode. In this embodiment, phase rotation in the high frequency region of the signal transmitted in the apparatus can be prevented. This means that image quality is improved, while at the same time high frequency noise can be reduced and EMI to other electronic devices can be prevented.

In another preferred embodiment of the method according to the second aspect of the present invention, the controller circuit converts the polarity inversion signal and the horizontal scan signal transmitted in parallel into a first series signal voltage. ; And a voltage-current conversion step of converting the first series signal voltage into a signal current. The signal current is output to the transmission line (s). The data electrode driving circuit includes a current-voltage conversion step of converting the signal current into a second signal voltage; And a series-parallel conversion step of converting the second signal voltage into the polarity inversion signal and the horizontal scanning signal in parallel.

In order to easily achieve the present invention, it will be described in connection with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail in connection with the accompanying drawings.

7 illustrates a circuit configuration of an LCD device according to an embodiment of the present invention. The apparatus includes an LCD panel 20, a controller circuit 30, a gray scale power supply circuit 40, a data electrode driving circuit 50, and a scan electrode driving circuit 60.

The LCD panel 20 includes a color filter that generates a color image by dividing each pixel into a red (R) sub-pixel, a green (G) sub-pixel, and a blue (B) sub-pixel. The panel 20 includes n data electrodes X1 to Xn (where n is a positive integer greater than 2) to which the corresponding sub-pixel data signal D is applied, and m to which the corresponding scanning signal V is applied. Scan electrodes Y1 to Ym (where m is a positive integer greater than 2), and a sub-pixel region formed at each intersection point between the data electrodes X1 to Xn and the scan electrodes Y1 to Ym ( Not shown). A corresponding sub-pixel data signal D is applied to a particular sub-pixel region selected by the scanning signal V, and the color image on the screen (not shown) of the panel 20 is in accordance with this signal D. Will be displayed.

For example, the controller circuit 30 formed of the ASIC provides 8-bit red data DR, 8-bit green data DG, and 8-bit blue data DB in the current mode to the data electrode driving circuit 50. do. These data DR, DG, and DB are provided to the circuit 30 from the outside of the LCD device. The circuit 30 may include a horizontal scan signal PH, a vertical scan signal PV, and a polarity inversion signal based on a horizontal sync signal SH, a vertical sync signal SV, and the like provided from the outside of the LCD device. POL). The polarity inversion signal POL is used to AC drive the panel 20 in predetermined periods (eg, periods of R, G, and B sub-pixels). The circuit 30 provides the generated horizontal scanning signal PH and the polarity inversion signal POL to the data electrode driving circuit 50 in the current mode in the form of a serial signal PH / POL. At the same time, the circuit 30 provides the thus generated vertical scan signal PV to the scan electrode driving circuit 60 in the current mode. The circuit 30 also provides red scale voltage data DGR, green scale voltage data DGG, and blue scale voltage data DGB to the gray scale power supply circuit 40, which provides gamma-correction. It is used to provide gradients to DR, DG, and DB, respectively.

The gray scale power supply circuit 40 includes three DAC circuits 41 ₁ , 41 ₂ , and 41 ₃ and 54 transmitter circuits 42 ₁ to 42 _{54 as} shown in FIG. 8.

The DAC circuit 41 ₁ converts the digital red scale voltage data DGR into analog red scale voltages V _R0 to V _R17 , after which the circuit 41 ₁ converts the analog voltages V _R0 to V _R17 . Are transmitted to the transmitter circuits 42 ₁ to 42 ₁₈ , respectively. Similarly, the DAC circuit 4 _{1 2} converts the digital green scale voltage data DGG to analog green scale voltages V _G0 to V _G17 , and the circuit 4 _{1 2} then converts the analog green scale voltages V _G0 to V _G17 ) is transmitted to the transmitter circuits 42 ₁₉ to 42 ₃₆ , respectively. The DAC circuit 4 ₁₃ converts the digital blue scale voltage data DGB into analog blue scale voltages V _B0 to V _B17 , after which the circuit 4 ₁₃ is an analog voltage V _B0 to V _B17 . Are transmitted to the transmitter circuits 42 ₃₇ to 42 ₅₄ , respectively. Analog red scale voltages V _R0 to V _R17 , analog green scale voltages V _G0 to V _G17 , and analog blue scale voltages V _B0 to V _B17 are red data DR, green data DG, and Used for gamma-correction for each blue data DB.

Transmitter circuits 42 ₁ to 42 _{18 receive} analog red scale voltages V _R0 to V _R17 at high input impedance, respectively, and convert them to analog red scale currents I _R0 to I _R17 , respectively. The circuits 42 ₁ to 42 _{18 then output the} analog red scale currents I _R0 to I _R17 thus obtained to the data electrode driving circuit 50 at low output impedance. Similarly, the transmitter circuit (42 ₁₉ to 42 ₃₆₎ is configured to receive the green analog scale voltage (V V _G0 to _G17) in a high input impedance, respectively, and converts each analog to green scale current (I _G0 to _G17 I). The transmitter circuits 42 ₁ to 42 _{18 then output the} analog green scale currents I _G0 to I _G17 thus obtained to the data electrode driving circuit 50 at low output impedance. Transmitter circuits 42 ₃₇ to 42 _{54 receive} analog blue scale voltages V _G0 to V _G17 at high input impedance, respectively, and convert them to analog blue scale currents I _B0 to I _B17 , respectively. The circuits 42 ₃₇ to 42 _{54 then output the} analog blue scale currents I _B0 to I _B17 thus obtained to the data electrode driving circuit 50 at low output impedance.

The data electrode driving circuit 50 includes k data electrode driving units 50 ₁ to 50 _k , where k is a natural number. Each of the data electrode drivers 50 ₁ to 50 _k converts the red, green, or blue data DR, DG, or DB provided from the controller circuit 30 into a voltage mode in the current mode, and then the circuit. 50 represents red, green, or blue data DR, DG, or so converted based on red, green, and blue scale currents I _R0 to I _R17 , I _G0 to I _G17 , I _B0 to I _B17 . Each gamma-correction is performed to provide a gradation. The circuit 50 then converts the thus converted and corrected red, green, and blue data DR, DG, and / or DB into 384 sub-pixel data signals D and then the signal ( D) is output to the data electrodes X1 to Xn on the panel 20.

For example, if the panel 20 is designed with SXGA resolution or mode and has a total of 1280 pixels (horizontal) x 1024 pixels (vertical), the number of sub-pixels is 3840 pixels (horizontal) x 1024 pixels (vertical) This is because each pixel is formed of a red sub-pixel, a green sub-pixel, and a blue sub-pixel. Here, (3840 pixels) / (384 data signals) = 10 (pixels / data signals). Therefore, the total number of data electrode drivers 10 is 10, that is, k = 10. This means that the data electrode driver circuit 50 includes ten data electrode drivers 50 ₁ to 50 ₁₀ . In the following, description will be made based on the above-described conditions.

The data electrode drivers 50 ₁ to 50 ₁₀ have the same circuit configuration except for each element and the subscript of each signal. Therefore, only the data electrode driver 50 ₁ will be described.

As shown in FIG. 9, the data electrode driver 50 ₁ of the data electrode driver circuit 50 includes a receiver (i.e., an IV converter) unit 75, three MPX circuits 51 ₁ to 51 ₃ , and It includes an 8-bit DAC circuits (52 ₁ to 52 _3), and 384 a voltage follower circuit (53 ₁ to 53 _384).

The receiver unit 75 receives the red, green, and blue scale currents I _R0 to I _R17 , I _G0 to I _G17 , I _B0 to I _B17 from the gray scale power supply circuit 40, and converts them to the red scale voltage ( V _R0 to V _R17 , green scale voltages V _G0 to V _G17 , and blue scale voltages V _B0 to V _B17 .

The MPX circuit 51 ₁ receives the red scale voltages V _R0 to V _R17 and then, in accordance with the polarity inversion signal POL from the controller circuit 30, of the red scale voltages V _R0 to V _R8 . The set or sets of red scale voltages V _R9 to V _R17 are alternately provided to the DAC circuit 52 ₁ . Similarly, the MPX circuit 5 _{1 2} receives the green scale voltages V _G0 to V _G17 , and then sets or green scales of the green scale voltages V _G0 to V _G8 in accordance with the polarity inversion signal POL. voltage (V _G9 to _G17 V) provides a set of the shift to the DAC circuit (52 ₂₎ is less. MPX circuit (51 ₃₎ is blue scale voltages (V _B0 to V _B17) to receive and, then, set or blue scale voltages (V a blue scale voltages (V _B0 to V _B8), depending on the polarity inversion signal (POL) to a set of V _B9 to _B17) provide a DAC circuit (52 ₃₎ alternately to the enemy.

The DAC circuit 52 ₁ is connected from the controller circuit 30 based on the set of red scale voltages V _R0 to V _R8 from the MPX circuit 51 ₁ or the set of red scale voltages V _R9 to V _R17 . A predetermined gamma-correction is performed on the 8-bit red data DR to provide gradation to the red data DR. In addition, the circuit 51 ₁ converts the digital red data DR corrected in this way into an analog red data signal, and then the corresponding voltage follower circuits 53 ₁ , 53 ₄ , 53 ₇ ,..., 53 ₃₈₂ To provide. Similarly, the DAC circuit 52 ₂ is based on a set of green scale voltages V _G0 to V _G8 or a set of green scale voltages V _G9 to V _G17 from the MPX circuit 51 ₂ . A predetermined gamma-correction is performed on the 8-bit green data DG from) to provide a gradation to the green data DG. In addition, the circuit 5 _{1 2} converts the digital green data DG thus corrected into an analog green data signal, and then the corresponding voltage follower circuits 53 ₂ , 53 ₅ , 53 ₈ , ..., 53 ₃₈₃ To provide. DAC circuit (52 ₃₎ from the controller circuit 30 based on the set of the MPX circuit (51 ₃₎ Blue scale voltages (V _B0 to V _B8) set or blue scale voltages (V _B9 to V _B17) of from A predetermined gamma-correction is performed on the 8-bit blue data DR to provide gradation to the blue data DB. In addition, the circuit (51 ₃₎ is thus the corrected digital data Blue (DB) and then converted to an analog blue data signals, corresponding to the voltage follower circuit (53 _3, 53 _6, 53 _9, ... to 53 ₃₈₄ To provide.

Voltage follower circuits 53 ₁ through 53 ₃₈₄ receive the corresponding red, green, and blue data signals provided from DAC circuits 52 ₁ , 52 ₂ ^, and 52 ₃ at high input impedance, and then at low output impedance. It is transmitted as a sub-pixel data signal D to the corresponding data electrodes X1 to Xn on the panel.

The scan electrode driving circuit 60 generates the scan signal V in synchronization with the vertical scan signal PV transmitted from the controller circuit 2. The circuit 60 then provides the generated scan signal V to the corresponding scan electrodes Y1 to Ym on the panel.

FIG. 10 shows an example of a circuit configuration of the transmitter unit 31 provided in the controller circuit 30 and the receiver unit 71 provided in the data electrode driving circuit 50. The transmitter section 31 functions as a "first interface circuit" and the receiver section 71 functions as a "second interface circuit", which causes the controller circuit 30 to function as a data electrode driving circuit 50. Is used for electrical connection.

As shown in FIG. 10, the transmitter section 31 includes a two-input OR circuit 32, two inverter circuits 33 and 34, and two n-channel MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). 35 and 36). OR circuit 32 functioning as a parallel-to-serial (PS) converter receives the horizontal scan signal PH and the polarity inversion signal POL and outputs a first signal voltage (PH / POL) _VOL . The first signal voltage (PH / POL) _VOL comprises pulses arranged in series of signals PH and POL. Functioning as a voltage-to-current (VI) converter, a set of inverter circuits 33 and 34 and MOSFETs 35 and 36 converts the first signal voltage (PH / POL) _VOL into a signal current ((PH / POL). ) _CUR1 ) and the signal current ((PH / POL) _CUR2 ). These two signal currents (PH / POL) _CUR1 and (PH / POL) _CUR2 vary complementarily with each other. The transmitter unit 31 is electrically connected to the receiver unit 71 through the transmission line 80. The signal currents (PH / POL) _CUR1 and (PH / POL) _CUR2 flow complementarily from the transmitter section 31 to the receiver section 71 via the corresponding line 81.

The polarity of the first signal voltage (PH / POL) _VOL is inverted by the inverter 33 to output the signal U. FIG. Thereafter, the signal U is inverted by the inverter 34 to output the signal W. FIG. The signals U and W are provided to gates of the MOSFETs 35 and 36, respectively, to complement or turn on the MOSFETs 35 and 36, respectively. As a result, complementary signal currents ((PH / POL) _CUR1 and (PH / POL) _CUR2 ) are generated.

The receiver portion 71 includes a current-voltage (IV) converter circuit 72 and a series-parallel (SP) converter circuit 73, as shown in FIG. 10. The IV converter circuit 72 converts the complementary signal currents (PH / POL) _CUR1 and (PH / POL) _CUR2 transmitted over line 80 to a second signal voltage ((PH / POL) ' _VOL ). do. The SP converter circuit 73 converts the second signal voltage PH / POL ' _VOL into a horizontal scan signal PH and a polarity inversion signal POL, which are output in parallel from the circuit 73. .

As shown in FIG. 7, the controller circuit 30 includes a transmitter unit 37 for horizontal scanning signal PV and a transmitter unit 38 for red, green, and blue data DR, DG, and DB. do. The transmitter unit 37 converts the horizontal scan signal PV (ie, (PV) _VOL ) in the voltage mode to the current mode (ie, (PV) _CUR1 and (PV) _CUR2 ), and then drives them in the scan electrode. Transfer to circuit 60. The transmitter unit 37 has the circuit configuration shown in FIG. 12, which is the same as the configuration obtained by removing the OR circuit 32 from the transmitter unit 31 for the signals PH and POL shown in FIG. Meanwhile, the transmitter unit 38 converts the red, green, and blue data DR, DG, and DB of the voltage mode to the current mode, and then transmits them to the data electrode driving circuit 50. The transmitter section 38 has the same circuit configuration as that shown in FIG. 12 for each of the data DR, DG, and DB.

The data electrode driving circuit 50 includes a receiver section 74 for red, green, and blue data DR, DG, and DB, and scale currents I _R0 to I _R17 , I _G0 to red, green, and blue. I _G17 , I _B0 to I _B17 ). The receiver unit 74 converts the red, green, and blue data (DR, DG, and DB) (ie, (DR) _CUR , (DG) _CUR , and (DB) _CUR ) of the current mode into a voltage mode (that is, ( DR) _VOL , (DG) _VOL , and (DB) _VOL ), respectively, and then transfer them to the data electrodes X1 to Xn on panel 20. The receiver section 74 has the circuit configuration shown in Fig. 13, which is the same as the configuration obtained by removing the SP converter 73 from the receiver section 71 for signals PH and POL (see Fig. 10). Meanwhile, the receiver unit 75 converts the red, green, and blue scale currents I _R0 to I _R17 , I _G0 to I _G17 , and I _B0 to I _B17 into a voltage mode. The receiver section 75 has substantially the same circuit configuration as that shown in FIG.

FIG. 11 is a timing diagram for describing an operation of the LCD device according to the exemplary embodiment of FIG. 7. The signal transmission method in this embodiment will be described below with reference to FIGS. 10 and 11.

In the LCD device of the embodiment of Fig. 7, as shown in Fig. 11, the polarity inversion signal POL and the horizontal scanning signal PH have their active mode periods at different timings. Specifically, when the horizontal scan signal PH is in the active mode (ie, the logic high level), the polarity inversion signal POL is not in the active mode but in the ineffective state. On the other hand, when the polarity inversion signal POL is in the active mode, the horizontal scanning signal PH is not in the active mode.

The polarity inversion signal POL and the horizontal scan signal PH, which are generated in parallel in the controller circuit 30, are OR circuits 32 of the transmitter section 31 that contain pulses of signals POL and PH that are aligned in series. Is converted into a first voltage signal (PH / POL) _VOL . This is a parallel to serial conversion process. After that, the first voltage signal (PH / POL) _VOL is a current signal (PH formed by the VI converter (formed by the inverters 33 and 34 and the MOSFETs 35 and 36) of the transmitter unit 31. / POL) _CUR1 and (PH / POL) _CUR2 ). This is a voltage-current conversion process. The complementary current signals (PH / POL) _CUR1 and (PH / POL) _CUR2 thus obtained are then transmitted to the receiver portion 71 of the data electrode drive circuit 50 via the transmission line 80.

In the receiver unit 71, the current signals (PH / POL) _CUR1 and (PH / POL) _CUR2 are converted into a second voltage signal (PH / POL) ' _VOL by the IV converter 72. . This is a current-voltage conversion process. Thereafter, the second voltage signal (PH / POL) ' _VOL is converted in parallel by the SP converter 73 into a polarity inversion signal POL and a horizontal scanning signal PH. This is a serial to parallel conversion process.

As shown in FIG. 9, the red scale currents I _R0 to I _R17 provided from the gray scale power supply circuit 40 are controlled by the receiver unit 75 of the data electrode driving circuit 50 in a voltage mode (ie, V). _R0 to _VR17 ). Then, they are input to the MPX circuit 51 _{1 in} synchronization with the horizontal scan signal PH. Then, according to the polarity inversion signal POL, a set of red scale voltages V _R0 to V _R8 or a set of red scale voltages V _R9 to V _R17 are alternately provided to the DAC circuit 51 ₁ . Similarly, the green scale currents I _G0 to I _G17 provided from the gray scale power supply circuit 40 are driven by the receiver unit 75 of the data electrode driving circuit 50 in the voltage mode (ie, V _G0 to V _G17 ). Is converted to. Then, they are input to the MPX circuit 5 _{1 in} synchronization with the horizontal scan signal PH. Then, in accordance with the polarity inversion signal POL, a set of green scale voltages V _G0 to V _G8 or a set of green scale voltages V _G9 to V _G17 are alternately provided to the DAC circuit 51 ₂ . The blue scale currents I _B0 to I _B17 provided from the gray scale power supply circuit 40 are converted into a voltage mode (ie, V _B0 to V _B17 ) by the receiver portion 75 of the data electrode driving circuit 50. . Then, all of which are in synchronism with the horizontal scanning signal (PH) is input to the MPX circuit (51 _3). Then, a set of the polarity inversion signal (POL) blue scale voltages (V _B0 to _B8 V) or a set of blue scale voltage (V V _B9 to _B17) in accordance with the provided alternately on the DAC circuit (51 _3).

8-bit red data provided from the controller circuit 30 and input to the DAC circuit 52 ₁ based on the set of red scale voltages V _R0 to V _R8 or the set of red scale voltages V _R9 to V _R17 . Gamma-correction is performed at (DR) to provide a gradation for the data DR. At the same time, the red data DR is converted into an analog red data signal. The analog red data thus obtained is provided to corresponding voltage follower circuits 53 ₁ , 53 ₄ , 53 ₇ ,..., And 53 ₃₈₂ . Similarly, 8- input provided from the controller circuit 30 and input to the DAC circuit 52 ₂ based on the set of green scale voltages V _G0 to V _G8 or the set of green scale voltages V _G9 to V _G17 . Gamma-correction is performed on the bit green data DG to provide gradation to the data DG. At the same time, the green data DG is converted into an analog green data signal. The analog green data thus obtained is provided to corresponding voltage follower circuits 53 ₂ , 53 ₅ , 53 ₈ ,..., And 53 ₃₈₃ . Based on a set of blue scale voltages (V _B0 to _B8 V) or a set of blue scale voltage (V V _B9 to _B17) provided from the controller circuit 30 and the 8-bit blue data input to the DAC circuit (52 ₃₎ Gamma-correction is performed at (DB) to provide gradation to the data (DB). At the same time, the blue data DB is converted into an analog blue data signal. The analog blue data thus obtained is provided to corresponding voltage follower circuits 53 ₃ , 53 ₆ , 53 ₉ ,..., And 53 ₃₈₄ .

The analog red, green, and blue data signals thus obtained are transmitted as corresponding sub-data signals D to the corresponding data electrodes X1 to Xn.

The vertical scan signal PV is provided from the controller circuit 30 to the scan electrode driving circuit 60. The scan signal V is generated by the circuit 60 and output to the scan electrodes Y1 to Ym in synchronization with the signal PV. In the panel 20, the sub-pixel data signal D is provided to each of the predetermined sub-pixel areas selected by the scanning signal V, and the panel 20 in accordance with the sub-pixel data signal D provided in this way. Display a predetermined color image on the screen (not shown).

In the LCD device according to the embodiment of the present invention described above, the horizontal and vertical scan signals PH and PV, the polarity inversion signal POL, the red, green, and blue data DR, DG, and DB, and The red, green, and blue scale voltages V _R0 to V _R17 , V _G0 to V _G17 , V _B0 to V _B17 are all converted to current mode, and then they are transmitted over transmission line 80. Therefore, phase rotation in the high frequency region of the signal transmitted in the apparatus is effectively prevented or suppressed, thereby improving the quality of the image on the screen of the panel 20. In addition, since high frequency noise is suppressed, EMI to other electronic devices can be prevented.

In addition, the horizontal scan signal PH and the polarity inversion signal POL are transmitted to the data electrode driving circuit 50 in series in the current mode through a common transmission line. Thus, the total number of transmission lines required is reduced. This means that the device of this embodiment can cope with the tendency of miniaturization.

The above embodiment is a preferred embodiment of the present invention, and the present invention is not limited to the above embodiment. Modifications and variations may be made to the above embodiments within the spirit of the invention.

For example, the period for driving the LCD 20 panel may be set equal to the period of a predetermined horizontal line or one frame period. The circuit configuration of the transmitter section 31 of the controller circuit 30 can be arbitrarily changed as long as it has a function of converting the signal voltage PH / POL into the current mode.

While the preferred embodiments of the invention have been described, variations will be apparent to those skilled in the art without departing from the spirit of the invention. Accordingly, the scope of the invention is to be determined only by the following claims.

1 is a block diagram showing a configuration of an example of a conventional LCD device.

FIG. 2 is a block diagram showing the configuration of a gray scale power supply circuit used in the LCD device of the prior art of FIG.

3 is a block diagram showing the configuration of a data electrode driver of the data electrode driver circuit used in the LCD device of the prior art of FIG.

Fig. 4 is a schematic diagram showing a mounting state of a data electrode driver of the data electrode driver circuit of the LCD device of the prior art of Fig. 1;

Fig. 5 is a schematic diagram showing a mounting state of a data electrode driver, a backlight unit, and an LCD panel of a data electrode driving circuit of the prior art LCD device of Fig. 1;

Fig. 6 is a timing diagram showing the operation of the LCD device of the prior art shown in Fig. 1, showing only the horizontal scanning signal PH and the polarity inversion signal POL.

7 is a block diagram showing a configuration of an LCD device according to an embodiment of the present invention.

FIG. 8 is a block diagram showing the configuration of a gray scale power supply circuit used in the LCD device according to the embodiment of FIG.

9 is a block diagram showing a configuration of a data electrode driver of a data electrode driver circuit used in the LCD device according to the embodiment of FIG.

10 is a configuration of a receiver unit (i.e., a second interface circuit) provided in a data electrode driving circuit used in the LCD device according to the embodiment of FIG. 7 and a transmitter unit (i.e., a first interface unit) provided in a controller circuit. Schematic block diagram illustrating the invention.

FIG. 11 is a timing diagram illustrating an operation of the LCD device according to the embodiment of FIG. 7. In addition to the horizontal scanning signal PH and the polarity inversion signal POL, the current-mode signal PH / POL is transmitted in series. Drawing).

FIG. 12 is a schematic circuit diagram of a transmitter section provided in the controller circuit of the LCD device according to FIG. 7 and used for converting the vertical scan signal PV in the voltage mode to the current mode. FIG.

FIG. 13 is a schematic circuit diagram of a receiver unit provided in a data electrode driving circuit of the LCD device according to the embodiment of FIG. 7 and used to convert red, green, and blue data of a current mode into a voltage mode. FIG.

♠ Explanation of the symbols for the main parts of the drawings.

20: LCD panel 30: controller circuit

31 transmitter 40 gray scale power supply circuit

41 ₁ , 41 ₂ , and 41 ₃ : DAC circuits 42 ₁ to 42 ₅₄ : Transmitter circuits

50: data electrode driver circuit 50 ₁ to 50 _k : data electrode driver

51 ₁ to 51 ₃ : MPX circuit 52 ₁ to 52 ₃ : 8-bit DAC circuit

53 ₁ to 53 ₃₈₄ : voltage follower circuit 60: scan electrode driving circuit

75: receiver

Claims (7)

A liquid crystal display (LCD) panel having a data electrode for receiving a pixel data signal, a scan electrode for receiving a scan signal, and a pixel region located at an intersection of the data electrode and the scan electrode; Receive an image input signal in synchronization with a horizontal scan signal, polarize the pixel data signal corresponding to the image input signal based on the polarity inversion signal, and apply the polarity inverted pixel data signal to the data electrode of the panel. A data electrode driving circuit for transmitting the data; A scan electrode driving circuit for transmitting a scan signal to the scan electrode of the panel in synchronization with a vertical scan signal; And A controller circuit for outputting said image input signal, said polarity inversion signal, said horizontal scanning signal and said vertical scanning signal, A portion of the pixel region is selected by the scan signal, Wherein the pixel data signal is provided to the portion of the pixel region and displays an image corresponding to the applied pixel data signal, The controller circuit receives the polarity inversion signal and the horizontal scanning signal in parallel with different active mode periods, generates a serial signal from the polarity inversion signal and the horizontal scanning signal, and transmits the serial signal to the transmission line (s). A first interface circuit for transmitting to said data electrode driving circuit via; And the data electrode driving circuit includes a second interface circuit which regenerates the polarity inversion signal and the horizontal scanning signal in parallel from the serial signal. The method of claim 1, And the device has a configuration in which the serial signal is transmitted in a current mode. The method of claim 1, The first interface circuit includes a parallel-to-serial converter circuit for converting the polarity inversion signal and the horizontal scan signal transmitted in parallel into a first series signal voltage; And a voltage-to-current converter circuit for converting the first series signal voltage to a signal current; The signal current is output to the transmission line (s); The second interface circuit includes a current-voltage converter circuit for converting the signal current into a second signal voltage; And a series-parallel converter circuit for converting the second signal voltage into the polarity inversion signal and the horizontal scanning signal in parallel. The method of claim 1, And the data electrode driving circuit includes at least one data electrode driving unit according to the number of data electrodes. A liquid crystal display (LCD) panel having a data electrode for receiving a pixel data signal, a scan electrode for receiving a scan signal, and a pixel region located at an intersection of the data electrode and the scan electrode; Receive an image input signal in synchronization with a horizontal scan signal, polarize the pixel data signal corresponding to the image input signal based on the polarity inversion signal, and apply the polarity inverted pixel data signal to the data electrode of the panel. A data electrode driving circuit for transmitting the data; A scan electrode driving circuit for transmitting a scan signal to the scan electrode of the panel in synchronization with a vertical scan signal; And A controller circuit for outputting said image input signal, said polarity inversion signal, said horizontal scanning signal and said vertical scanning signal, A portion of the pixel region is selected by the scan signal, A signal transmission method in an LCD device, wherein the pixel data signal is provided to the portion of the pixel area, and displays an image corresponding to the applied pixel data signal. Receiving, in the controller circuit, the polarity inversion signal and the horizontal scanning signal in parallel with different active mode periods; Generating a serial signal from the polarity inversion signal and the horizontal scan signal; And transmitting said serial signal to said data electrode driving circuit via a transmission line (s), And reproducing the polarity inversion signal and the horizontal scanning signal in parallel from the serial signal in the data electrode driving circuit. The method of claim 5, The serial signal is transmitted in a current mode. The method of claim 5, The controller circuit converts the polarity inversion signal and the horizontal scanning signal transmitted in parallel into a first series signal voltage; And a voltage-current conversion step of converting the first series signal voltage into a signal current; The signal current is output to the transmission line (s); The data electrode driving circuit includes a current-voltage conversion step of converting the signal current into a second signal voltage; And a serial-to-parallel conversion step of converting the second signal voltage into the polarity inversion signal and the horizontal scanning signal in parallel.